Add --prefer-integrity option to manifest_fixer.py

If provided (--prefer-integrity=true/false), the script will set the
value in the the manifest.  The script will fail if the value mismatches
the original in the manifest, if any.

Test: scripts/manifest_fixer_test.py
Test: aapt dumps the attribute and observe
Bug: 112037137
Change-Id: I2b333a7c0747dbcbed4d419f1c9ed46d4a4c98e9